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| Euclid Mission Assessment Study - Executive Summary (Thales Alenia Space) |
| The Euclid Mission Assessment Study is the industrial part of the Euclid assessment phase. This document summarizes the results of one such study performed between September 2008 and September 2009 by a team led by Thales Alenia Space (I) and including Thales Alenia Space (F), Kayser-Threde and Deimos Space. |
| Publication date: 30 Oct 2009 |
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| Technical Review Report - Marco Polo |
| Reference: SRE-PA/2009.069/Marco-Polo This technical review report for the Marco Polo candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level. |
| Publication date: 30 Oct 2009 |
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| Kinetic Alfvén waves turbulence in the Earth's magnetosphere |
| The numerical simulations of the model equation governing the nonlinear dynamics of kinetic Alfvén waves in the intermediate-beta plasmas are performed. When the nonlinearity arises due to the ponderomotive force driven density perturbations of kinetic Alfvén waves, the model equation turns out to be a modified nonlinear Schrödinger equation. This has been solved numerically by using appropriate boundary conditions. The coherent, damped magnetic filaments with turbulent spectra have been observed. Our results reveal the interesting change in spectral index because of the damping effect. The steeper power spectra follow ~k-3.4 scaling. Using the Fokker-Planck equation with the new velocity space diffusion coefficient, we find the distribution function of energetic electrons in these turbulent structures. These turbulent structures can be responsible for plasma heating in Earth's magnetosphere. |
| Publication date: 28 Oct 2009 |
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| Disappearing induced magnetosphere at Venus: Implications for close-in exoplanets |
| The solar wind interaction with a planetary atmosphere produces a magnetosphere-like structure near the planet whether or not the planet has an intrinsic global magnetic field. In the case of planets like Venus or Mars, which have no global intrinsic magnetic field but possess a significant atmosphere, a magnetosphere is induced in the highly conducting ionosphere by the time-varying magnetic field carried by the solar wind. The induced magnetosphere at Venus and Mars is almost a "permanent" feature of the solar wind interaction. Here we report a Venus Express observation of the absence of the dayside part of the induced magnetosphere, when the interplanetary magnetic field (IMF) is nearly aligned with the solar wind flow. Using MHD simulations for this extreme IMF orientation, we examine the global interaction of the solar wind with Venus when the magnetic barrier disappears. Furthermore, we estimate the atmospheric loss under this extreme situation. While this solar wind aligned IMF interaction with a planet case is presently rare, and even rarer over solar system history, it might be an appropriate analogue of the interaction of a stellar wind with close-in exoplanet. Thus the solar wind interaction with Venus under this extreme condition might provide us a natural laboratory for studying the evolution of the atmospheres of "hot Jupiters" as well as close-in "terrestrial" planets. |
| Publication date: 27 Oct 2009 |
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| Astronomy & Astrophysics special issue - The CoRoT space mission: early results |
This A&A special issue is devoted to the CoRoT (Convection, Rotation & planetary
Transits) space mission. Launched on 27 December 2006, the satellite moves in a polar circular
orbit, and the CCD camera of its 27-cm telescope measures stellar-brightness variations with µmag
precision in equatorial fields close to the galactic plane.
The main science goals of CoRoT are to discover exoplanets by the transit method and detect
seismic waves in stars across the entire Hertzsprung-Russell diagram. Objectives also include the
study of stellar activity, stellar rotation, and eclipsing multiple systems.The first results obtained
with CoRoT in all these scientific areas are discussed in the pages of this special issue. |
| Publication date: 22 Oct 2009 |
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| PLATO Mission Assessment Study - Executive Summary (Astrium) |
| The PLATO Mission Assessment Study is the industrial part of the PLATO assessment phase. Two parallel 1-year assessment studies have been concluded. This report is the executive summary for the study performed by EADS-Astrium |
| Publication date: 20 Oct 2009 |
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| Universality of Solar-Wind Turbulent Spectrum from MHD to Electron Scales |
| To investigate the universality of magnetic turbulence in space plasmas, we analyze seven time periods in the free solar wind under different plasma conditions. Three instruments on Cluster spacecraft operating in different frequency ranges give us the possibility to resolve spectra up to 300 Hz. We show that the spectra form a quasiuniversal spectrum following the Kolmogorov's law ~k-5/3 at MHD scales, a ~k-2.8 power law at ion scales, and an exponential ~exp[-sqrt(k rhoe)] at scales k rhoe~[0.1,1], where rhoe is the electron gyroradius. This is the first observation of an exponential magnetic spectrum in space plasmas that may indicate the onset of dissipation. We distinguish for the first time between the role of different spatial kinetic plasma scales and show that the electron Larmor radius plays the role of a dissipation scale in space plasma turbulence. |
| Publication date: 14 Oct 2009 |
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| Energetic electron response to ULF waves induced by interplanetary shocks in the outer radiation belt |
| Strong interplanetary shock interactions with the Earth's magnetosphere have great impacts on energetic particle dynamics in the magnetosphere. An interplanetary shock on 7 November 2004 (with the maximum solar wind dynamic pressure of ~70 nPa) was observed by the Cluster constellation to induce significant ULF waves in the plasmasphere boundary, and energetic electrons (up to 2 MeV) were almost simultaneously accelerated when the interplanetary shock impinged upon the magnetosphere. In this paper, the relationship between the energetic electron bursts and the large shock-induced ULF waves is studied. It is shown that the energetic electrons could be accelerated and decelerated by the observed ULF wave electric fields, and the distinct wave number of the poloidal and toroidal waves at different locations also indicates the different energy ranges of electrons resonating with these waves. For comparison, a rather weak interplanetary shock on 30 August 2001 (dynamic pressure ~2.7 nPa) is also investigated. It is found that interplanetary shocks or solar wind pressure pulses with even small dynamic pressure change can have a nonnegligible role in the radiation belt dynamics. |
| Publication date: 10 Oct 2009 |
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| Kinetic theory for the ion humps at the foot of the Earth's bow shock |
| The nonlinear kinetic theory is presented for the ion acoustic perturbations at the foot of the Earth's quasiperpendicular bow shock, that is characterized by weakly magnetized electrons and unmagnetized ions. The streaming ions, due to the reflection of the solar wind ions from the shock, provide the free energy source for the linear instability of the acoustic wave. In the fully nonlinear regime, a coherent localized solution is found in the form of a stationary ion hump, which is traveling with the velocity close to the phase velocity of the linear mode. The structure is supported by the nonlinearities coming from the increased population of the resonant beam ions, trapped in the self-consistent potential. As their size in the direction perpendicular to the local magnetic field is somewhat smaller that the electron Larmor radius and much larger that the Debye length, their spatial properties are determined by the effects of the magnetic field on weakly magnetized electrons. These coherent structures provide a theoretical explanation for the bipolar electric pulses, observed upstream of the shock by Polar and Cluster satellite missions. |
| Publication date: 05 Oct 2009 |
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| Technical Review Report - Cross-Scale |
| Reference: SRE/PA/2009/068 This technical review report for the Cross-Scale candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level. |
| Publication date: 05 Oct 2009 |
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| PRODEX Programme and ESA |
Presentation of the PRODEX Programme and its position within ESA to the Greek scientific community, given at the Hellenic Astronomical Conference in Athens, which was held on 4 September 2009.
Main topics covered:
- PRODEX - Position within ESA
- PRODEX - Introduction
- PRODEX - Its framework
- PRODEX - Which topics?
- PRODEX - How does it work?
- PRODEX - The running projects
- PRODEX - The people
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| Publication date: 01 Oct 2009 |
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